M1 carbine project, oh its weird

Discussion in 'Firearms' started by oil pan 4, Aug 20, 2020.


  1. oil pan 4

    oil pan 4 Monkey+++

    That's the gun portion of making a quiet weapons system.
    Let's say the gun and ammo is the control, so the silencer has to work around the parameters of the gun.
    A 24 inch bbl bolt 22lr firing subs with no muzzel device will be way quieter than an AR10 with any silencer.
    So the only way to be kind of fair is compare different silencers on a certain gun.
    Comparing 9mm silencers against other 30 cal silencers on a 30 cal isn't really fair either because that big 10mm hole let's out a lot of gas really fast but it's reasonable to assume someone could have a 9mm silencer and be able to screw it on a 30cb or 300bo.
     
    Last edited: Nov 27, 2020
    Gator 45/70 likes this.
  2. Merkun

    Merkun furious dreamer

    Not quite, but -- A suppressor can do a decent job of quieting muzzle blast from burning powder (no matter how much is packed into the cartridge) but they are totally ineffective at quieting the sonic crack from a supersonic bullet. Subsonics don't have the crack, 'cause they ain't going fast enough.
     
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  3. oil pan 4

    oil pan 4 Monkey+++

    It should be possible to quiet down a round with less faster burning powder.
    The normal load for a 30 carbine is say 15 or 16 grains of H110, it will get the bullet moving full 30 carbine velocity of up to 2000fps.
    But I could load something faster burning like 2400, loads I find listed loads use 10gr, it only gets your bullet going about 1,500 fps but there should be much less blast at the muzzel. It could reduce your uncorking pressure from say 5,000psi with H110 to 3,000 with the lower charge of 2400 that burned up and hit peak pressure much sooner.
    But I dont think it's worth giving up 500 fps in the 30 carbine to get a little quieter.

    Next peace carbine upgrade make a bandolier sling that holds 30cb on stripper clips.
     
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  4. Gator 45/70

    Gator 45/70 Monkey+++

    You can do it !
     
  5. oldman11

    oldman11 Monkey+++

    I had a Ruger single action .30 carbine that I had to get rid of because of it being too loud. Never again. Ears would ring for days
    [flag]
     
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  6. Gator 45/70

    Gator 45/70 Monkey+++

    Same here,Had a short barrel 308 in a box stand....Cha-zamm !!!
     
  7. arleigh

    arleigh Goophy monkey

    Accuracy in .30 carbine is shameful at best.
    I had a universal M1 carbine and a Ruger 30 single-action revolver hoping that the revolver would be more accurate than the rifle.
    After several hundred rounds through both, I concluded the ammo was junk and designed to be junk from its inception. a bullet that tumbles.
    Now things may have changed but for my money, I have plenty of other guns that fill my needs far better than 30 carbine even if it could fly straight.
     
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  8. oil pan 4

    oil pan 4 Monkey+++

    Mine was more accurate than expected with 110gr standard factory load ammo.
     
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  9. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    AlaskaChick’s Canp Rifle is a Universal M1 Carbine... It shoots well enough to drop a 350# Black Bear with one shot at about 30 yards... He is now a Nice Rug, in the Brown Cabin...I bought 1000 Rds for it, 15 years ago, and still have most of it in the Ammo Magazine...
     
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  10. oil pan 4

    oil pan 4 Monkey+++

    After stuff returns to normal I'm going to pick up a can packed on stripper clips.
    I think the Korean stuff I last saw was 700 or 800 rounds in a 30 cal ammo can.
     
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  11. oil pan 4

    oil pan 4 Monkey+++

    I'm going to load up a few hundred 84gr plated 8mm nimbu bullets I resized to 0.308''. Been working on a load for it with AA9 since I have more AA9 than I know what to do with. I worked up to 14.6gr, velocity was great around 2,360fps but it was leaving a bolt face impression on the brass, not good. I had no over pressure signs at the prior load increment of 14.3gr, but 14.3gr was probably producing over pressure with out obvious over pressure signs. So I'll back off to 14.0 to 14.1gr. At 14gr I was getting nearly 2,300fps.
     
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  12. oil pan 4

    oil pan 4 Monkey+++

  13. Gator 45/70

    Gator 45/70 Monkey+++

  14. hot diggity

    hot diggity Monkey+++ Site Supporter+++

    The MG Looks very industrial.

    I was hoping to read about some load development for subsonic .30 Carbine ammo that would still cycle the action. I've found Alliant 2400 to be almost magical stuff for making things move without a lot of recoil. I really discovered its potential while developing fixed piston cattle gun loads. We had a weighted pendulum and a camera set up to record the distance that each test powder would swing the pendulum. All the fast powders that I thought had potential were flops, maybe swinging the pendulum 3-5". Then the 2400 load was tested. It made 56" and we had to reduce the powder charge top get it within the working range of cattle or hog loads. I later found that it was the ideal powder for things like the Ruger .44 carbine. The powder has enough force to get the big bullet moving and enough pressure to operate the gas system without hammering my shoulder or throwing brass behind the soda machine. Best of all, accuracy is excellent.

    I think a slightly heavier than normal .30 Carbine bullet and a powder charge that will accelerate that bullet to subsonic speeds at the muzzle AND cycle the action reliably is possible. .30 carbine case capacity is 21cc while .300 Blackout is 19.2cc. Test the feeding with plated bullets with a big flat meplat and you might get the bullet weight maxed out before you reach the limits of the magazine.

    Sounds like a load that'll either be a lot of fun and very satisfying, or incredibly frustrating and no fun at all. Let us know how it goes.
     
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  15. oil pan 4

    oil pan 4 Monkey+++

    Nope, m1 carbines have 1:20 rifling.
    If you slow a small bullet down to subsonic, they won't cycle the gun and if you try to go heavier they won't stabilize at subsonic speed.
     
  16. hot diggity

    hot diggity Monkey+++ Site Supporter+++

    Original M1 carbine barrels may be fast twist, but a custom subsonic carbine barrel could be 1:7.

    If it's going to be a dedicated subsonic shooter you might as well jump in on the deep end and go all the way.
     
  17. oil pan 4

    oil pan 4 Monkey+++

    The cost of making a subsonic barrel will exceed the cost just getting a 300 blackout.
     
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  18. Gator 45/70

    Gator 45/70 Monkey+++

    Zimmy likes this.
  19. hot diggity

    hot diggity Monkey+++ Site Supporter+++

    That's what makes it unique. If it was easy and inexpensive everybody would be doing it. ;)
     
  20. oil pan 4

    oil pan 4 Monkey+++

    Plus I like the screaming velocity I get with the 1 in 20 twist barrel.
     
    Zimmy likes this.
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